1. Field of the Invention
The present invention generally relates to reading and writing information on a plurality of closely adjacent magnetic stripes on a card-like document, such as an airline ticket, and more particularly to an improved pressure pad for urging the stripes on the document into continuous contact with the transducer head.
2. Description of the Prior Art
The airline industry has adopted and is introducing a standard ticket for passengers. This ticket comprises a document in which alphanumeric information is printed on one side and magnetically encoded on four parallel magnetic tracks on the other side. The tracks are about three-sixteenths of an inch wide and separated by a gap on the order of fifteen-one-thousandth of an inch. The transducing head used to record and read information on the tracks advantageously includes both a reading transducer and a writing transducer, with the readwrite transducer separated by a small gap, on the order of three-hundred-fifty-thousandths of an inch.
It will be appreciated that all of the tracks must be kept continuously in contact with the transducent head, which is difficult to accomplish owing to the relatively large cumulative width of the four tracks. If too much pressure is applied to the document as it passes under the head there is a tendency to jam the operation. At lower pressures, using prior art pressure devices, such as rollers, there is a tendency for the pressure pad to vibrate so that reliable contact cannot be made between the transducing head and the magnetic stripes across all four tracks, a condition necessary for satisfactory operation.